The present invention relates to the field of microelectronics and more particularly to microelectronic patterning.
As integrated circuit devices become more highly integrated, dimensions of structures such as conductive lines and via holes and spaces therebetween are reduced. Accordingly, patterning processes are needed for smaller patterns. In the past, conventional optical lithography techniques have been used.
In optical lithography, an image of a pattern is optically projected onto a substrate by transmitting radiation through a mask including the pattern thereon. In essence, a pattern from a mask is projected onto a photosensitive material which is then developed so that the developed photosensitive material has the pattern of the mask. As the dimensions of microelectronic structures are further reduced, however, mask projection techniques may limit further reductions in pattern sizes.
Accordingly, there continues to exist a need in the art for improved patterning methods and systems.
According to embodiments of the present invention, a layer on a substrate can be patterned using interference patterns. For example, coherent radiation can be projected toward a reflector surface so that the coherent radiation is reflected off the reflector surface to provide a holographic projection of a desired image wherein the reflector surface includes information that corresponds to an inverse of the holographic projection of the desired image. The substrate including the layer can be maintained in the path of the reflected radiation so that the interference pattern is projected onto the layer. Accordingly, the holographic projection of the desired image can be used to patter the layer. For example, after maintaining the substrate including the layer in the path of the reflected radiation, the layer can be developed so that portions thereof are maintained and removed according to the intensity of the holographic projection of the desired image projected thereon.
Methods and systems according to embodiments of the present invention can thus provide patterning for microelectronic structures having relatively fine dimensions. Moreover, defect tolerance can be increased because the effect of a defect on the reflector surface is distributed throughout the interference pattern projected onto the surface of the layer being patterned.